I needed to merge the branch changes into trunk of the project, after many changes at both the branch and trunk…
First we have to commit all changes, in case of some failure at the merge operation we may revert all changes.
Select from menu, select the path of the branch and the revision. Revision number is selected from the Show Log, and is number when we created the branch.
Some useful links for SVN merge:
Eclipse SDK – Subversion Eclipse Plugin Manual



Some of the Subclipse developers also developed an enhanced merged client on top of Subclipse. This is part of the CollabNet Desktop, a free open-source licensed product. Information on the merge client is here:
http://desktop-eclipse.open.collab.net/servlets/ProjectProcess?pageID=MEuUjb
The CollabNet Desktop adds functionality on top of Subclipse.